1. Technical Field
The present disclosure relates to a kerf of a winter tire, and more particularly to a kerf of a winter tire that is capable of easily discharging snow therefrom while additionally further improving braking performance and drainage performance on a wet road.
2. Description of the Related Art
In general, a tire is one of the components constituting a vehicle. The tire directly contacts a road surface. Air in the tire absorbs shocks like a spring. Specifically, the air in the tire absorbs shocks generated due to irregularity of the road surface to improve comfort in driving of the vehicle.
The tire includes a tread, which is a rubber layer that contacts the road surface, a sidewall connected to the tread, the sidewall constituting a side surface of the tire, a bead connected to the sidewall, the bead being fixed to a rim of each wheel of the vehicle, a carcass mounted in the tire, the carcass forming a framework of the tire and exhibiting high fatigue resistance to bending and stretching of the sidewall, and a belt disposed between the tread and the carcass in order to protect the carcass and improve the rigidity of the surface of the tread. The tread includes a block and a groove. A kerf is formed in the block. The rigidity of the block is appropriately adjusted by the kerf so as to satisfy the requirements of the tire.
The application of the kerf to the surface of the tire provides better braking, steering, and traction performance on a snowy road. However, the application of the kerf lowers the rigidity of the tread block and degrades handling performance on a dry road or a wet road. Therefore, three-dimensional kerfs have recently been developed to prevent deterioration in rigidity attributable to application of the kerfs.
A three-dimensional tread kerf is disclosed in Korean Patent Laid-open Publication No. 2016-0022057, filed by the present applicant. Korean Patent Laid-open Publication No. 2016-0022057 discloses a tread kerf of a snow tire that is capable of securing the performance (steering, braking, traction, etc.) of the tire on a dry road and a wet road while additionally securing the performance of the tire on a snowy road and an icy road and that is capable of maintaining uniform rigidity of the block irrespective of the directionality of the kerf, maximizing the interlocking effect at the large surfaces, and maintaining uniform traction performance of the tire even when the tire is severely worn.
In addition, Korean Patent Registration No. 10-1037410 filed by the present applicant discloses a tread kerf of a heavy-duty tire that has improved heat-dissipation performance, improved durability, and improved drainage performance, thereby securing higher braking performance of the tire on a wet road.
However, because the amount of snowfall has recently decreased due to abnormally high temperatures in the winter, there is a need for a tire having further improved braking performance and drainage performance on a wet road while maintaining the function of the kerf on a snowy road.
When the tire rolls on a snowy road, snow may be introduced into a small gap defined by the kerf. This lowers a so-called “cohesion effect”, which is generated when the kerf scrapes compressed snow. Therefore, it is required to discharge snow from the kerf.
A snow tire having improved snow discharge performance is disclosed in Korean Patent Registration No. 10-1287507, filed by the present applicant. Korean Patent Registration No. 10-1287507 discloses a pneumatic heavy-duty snow tire, in which snow-discharge grooves are formed in the block, which is arranged between the grooves, at regular intervals in the circumferential direction of the tire and in which compressed air passages extend at an incline from the surface of the block to portions near the bottoms of the snow-discharge grooves, thereby rapidly discharging snow, which is introduced into a gap in the block of the tread when the block contacts snow on the surface of a snowy road, consequently improving the snow performance of the tire.